Transportation datasets of all kinds are hierarchical in nature, and therefore easily represented in
tree structures. Visually comparing the changes in these hierarchical datasets over time can be
extremely difficult, even when the trees are relatively small. TreeVersity is a novel interactive
visualization that allows users to detect and analyze changes in the structure and value of various
components of the tree. TreeVersity uses dual comparison techniques (side-by-side and explicit
differences) coupled with a tabular representation to help users understand and explore changes to
the tree over time. It uses carefully selected color palettes to show positive/negative, absolute and
relative value changes; and glyphs that preattentively show these changes. This paper illustrates the
value of this visualization through several short case studies using Federal transportation budget
data, airline maintenance budgets, transportation publication data, and hypothesizes about
TreeVersity’ s relevance for future congestion trend analysis. Video demonstrations of this research
can be viewed at http://tinyurl.com/treeversity.